Why is there still electricity when the three phase electric switch is turned off?

Load switchesOr it is a circuit breaker, which may be a short circuit current, the insulation isolation function of the switch has declined, although the switch is turned off, but there is still a certain amountLeakage current, but due to the large resistance, although the motor does not rotate, the person is electrocuted andTest penBrightness is not a problem. It is recommended to replace it with a new one.

Three-phase alternating current.

It is a form of transmission of electrical energy, referred to as three-phase electricity.

Three-phase AC power is made up of three frequencies of the same amplitude.

A power supply consisting of an alternating current potential that is equal and 120° different in phase.

Three-phase alternating current has many uses, and most of the alternating current electrical equipment in the industry, such as motors, use three-phase alternating current, which is often referred to as the three-phase four-wire system.

In daily life, single-phase power supply, also known as lighting electricity, is mostly used.

When lighting electricity is used, one of the three phases is used to supply power to the opposite electrical device, such as household appliances, and the other wire is the fourth wire in the three-phase four wires, that is, the neutral line, which is from the neutral point of the three-phase electricity. Elicit.

I don't know what the three-phase switch you use is, the load switch or the circuit breaker, which may be the short-circuit current, the insulation isolation function of the switch has declined, although the switch is turned off, but there is still a certain leakage current, but due to the large resistance, although the motor will not rotate, but the electric shock and the test pen is not a problem. It is recommended to replace it with a new one.

What is the switch, guillotine switch or contactor, carefully see if all three phases are disconnected, maybe the other two phases are disconnected, and a certain phase is not completely disconnected, (such as a contactor contact is adhesive, or the insulation resistance is low). One wire has electricity, three-phase motor naturally has electricity on all three lines, but can not form a current loop, of course the motor does not work, but people will be electrocuted, I have encountered a contactor contact sticking situation.

When one phase is missing, the current of the other two phases will increase suddenly, which will burn the switching power supply and burn the electrical equipment.

20 years ago, I saw a three-phase switch failure, which was very similar to the questioner's question. After inspection, it was found that the three-phase switch had a cut-off potential.

There is a short circuit phenomenon at the contact of the first phase and cannot be separated. In this case, it is assumed that the A-phase contact is adhesion. Phase A current enters the motor and then from phase B to phase C of the motor.

Winding outflow. At this point, the wires on the motor are still alive and all three wires are electrified. The lights are also lit with an electric pen. It's just that the motor doesn't work.

Yu may be this strange fault.

Solution: Replace the three-phase electric switch.

Summary. Hello dear, about the question you want to consult, "why is there electricity below the three-phase empty power off" as follows: the three-phase four-wire system of the big air power is broken and there is electricity behind the electricity, it may be that the air open contact adhesion is not broken, you can remove the air open line and then test whether there is electricity If there is no power to prove that there is a problem with the air opening, we must replace the air open and replace the air open, if it is a three-phase four-wire system of zero protection, the zero line has electricity, then it means that there is a three-phase electrical imbalance in this line, We have to look again to see if there is an imbalance in front of us.

Hello dear, about the question you want to consult, "why is there electricity below the three-phase empty power cut-off" is as follows: the three-phase four-wire system of the big air power is broken and there is electricity behind the electricity, it may be that the air open contact adhesion is not broken, you can remove the air open lower line and then test whether there is electricity If there is no electricity to prove that there is a problem with the empty open shed Huai, we must be more chain Sakura friends to change the empty open to change the empty open on the good, if it is a three-phase four-wire system of zero protection, the zero line has Songchang electricity, it means that there is a three-phase electrical imbalance in this line, We have to look again to see if there is an imbalance in front of us.

Normal switching power supply will not have this phenomenon. The switching power supply housing will be live, in most cases 1It is caused by the insulating ability of electronic components.

2.There is also inductive leakage caused by poor grounding. This requires a simple judgment, and it can be judged by ingenuity.

First grounding the switching power supply shell, and then powering on detection, if it disappears this phenomenon of impulse selling, it means that it is the role of induced voltage. If the voltage in the shell can still be detected after grounding, it means that it is a problem of poor circuit insulation. Fault points can be detected and judged based on the current state of the circuit.

What's going on with the three-phase electricity turned off and the electricity, hello, there is still induction electricity after the three-phase air switch is powered off, there are five possibilities: 1. There is a self-unused power-off circuit in the switch, which is the electricity of the electronic components; 2. The zero line is through the spine (the switch does not control the zero line), and the zero line is not well grounded; 3. The inlet and outlet lines are together, too close to each other, forming capacitors. 4. Open and dry carefully, close the water or air humidity is too large, and the insulation is poor.

5. There is a problem with the switch (such as contact with fire).

Hello, the neutral line is connected from the neutral point of the transformer, if the three-phase load of the transformer is unbalanced, it will generate a voltage to ground at the neutral point, this phenomenon is called neutral point drift, then there will be current flowing on the neutral line. In addition, it is possible that there is a leakage of the live wire at the upper port of the switch to the zero loss nuclear line or a short circuit, and the switch adhesion is not completely disconnected. Another situation is that there may be leakage of other equipment, resulting in the zero line of the excitation.

What is going on with the three-phase power turned off and the electricity, 1, it may be the zero line leakage at the power supply access end, the leakage may also be the fire wire leakage, or it is possible that both are leaking! Because it is not a leakage switch, it will not trip, unless the neutral live wire is leaking to bypass the load, forming a short circuit, and it will trip when it is empty! The main function of the air open is overload, short circuit, and three-phase unbalance protection!

2. It may be that the load is broken, such as the insulation of the motor winding is damaged, and it cannot reach the standard insulation value; Or the load is short-circuited and overloaded, the insulation layer is damaged where other currents pass, or the binding post leaks copper, like this Kailu rotten situation is connected to the reliable ground wire is not harmful to people, but the load can not be used.

It may be out of the spine to tease the three-phase empty power off, but there is still electricity below, which is due to the following reasons: 1The three-phase empty switch only disconnects the power supply to one of the phases, resulting in the other two phases still having power and therefore still being able to supply power.

2.There are problems in the cables, such as open circuits, etc., which cause only one of the three phases to be able to transmit power normally, and the other two phases to not be able to transmit, so only one phase can be energized for a short time. 3.

It is possible that the power supply does not enter from the three-phase empty switch, but it may enter through other transmission media (such as UPS, etc.), so it does not lose power when the three-phase air switch is powered off.

Hello according to your problem description: If the three-phase empty power is off but there is still electricity below, it may be caused by the following reasons: 1

The disconnection of one phase wire in a three-phase circuit results in an empty power break, but the remaining two phases are still energized, so there can be a current underneath. 2.The empty open contacts fail, causing the power to be cut off and the circuit cannot be cut, so there is still current underneath.

3.The empty opening itself is damaged and needs to be replaced. 4.

A short circuit caused by an excessive load causes an empty opening trip, but there is still power supply to other loads. 5.The empty open short circuit, causing the current to bypass the empty open, and there is still a current.